This invention relates to a method for analyzing samples using an immunoassay procedure, a competitive or displacement assay, which is structured to provide a system where multiple tests can be performed on different molecules at the same time. Immunoassay analysis is a widely used technique in medical and environmental testing. In the usual format, levels of one target molecule, the antigen, per sample per test are measured. This invention describes a method of testing where multiple tests are performed on the same sample in a molecule-specific manner. The sensitivity of the test system can be increased by combining antibody antigen interaction with a polymerase chain reaction (PCR) amplification step.
The most broadly used biodetection technologies are based on the use of antibodies. Antibodies recognize and bond to other molecules based on their shape and physicochemical properties. Antibodies are highly suited for detecting small quantities of target molecules in the presence of complex mixtures of other molecules.
One possible application of this technique is in medical diagnostics for which a large number of primary antibodies have already been developed. Development of phage that bind to these existing antibodies would allow the relatively near-term assembly of single technology cassettes which could provide the information of many diagnostic assays at the cost of a single assay.
A second application is in the area of environmental immunoassays in which the system would provide a broad spectrum evaluation of environmental samples. Applications could range from evaluation and monitoring of biological markers during environmental remediation efforts to assessment of soil, water, and air samples for the unnatural presence of elements within the tested environment.
Thus, the object of this invention is to provide a method which is capable of providing multiple tests to be run at the same time on different molecular samples.
Additional advantages, objects and novel features of the invention will become apparent to those skilled in the art upon examination of the following and by practice of the invention.
To achieve the foregoing and other advantages, this invention is a method for employing an immunoassay procedure in a test system to analyze samples. This method allows for multiple tests to be performed on different molecules at the same time. In the testing procedure, a target molecule, the antigen, is added to a solution containing an antibody to the antigen. To this antibody another secondary molecule having a specific DNA oligomer tag is bonded at the binding site for the antigen-antibody complex. Since the affinity of the antigen for the antibody is at least one order of magnitude greater than that of the antibody-secondary molecule, the secondary molecule is displaced. The secondary molecule is then isolated, and its presence is determine by the DNA-tag. Knowing of the presence of the secondary allows for the determination of the presence of the antigen.